FIG. 1 illustrates a known pencil beam proton therapy system (PBS) 10. The PBS 10 includes a proton beam source 100, beamline apparatus 110, beam detection apparatus 120, scan nozzle 130, and controller 140. In operation, proton beam source 100 generates a proton beam 101 at a requested energy level. The proton beam 101 is then trimmed and/or deflected by electromagnets in beamline apparatus 110. After passing through beamline apparatus 110, the proton beam 101 passes through beam detection apparatus 120, which can measure the location and intensity of the proton beam 101. The proton beam 101 then passes through scan nozzle 130, which includes electromagnets to deflect the beam to target locations in a patient, as represented by isocenter plane 150.
To avoid over-exposing the patient to proton beam 101, the controller 140 uses information from beam detection apparatus 120 to perform real-time calculations of the patient's exposure at defined volume elements or voxels in the patient. These real-time calculations rely on the measured position of proton beam 101, the measured intensity of proton beam 101, the beam energy (which determines the depth of exposure), and the exposure time at each measured position or voxel. As can be seen, these calculations require significant processor power to complete. In addition, the calculations rely on relatively complex software. Such software is expensive to develop and is subject to strict FDA regulations for medical devices.
It would be desirable to overcome one or more of the problems described above.